Whistling diesel

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P 2501
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Whistling diesel

Post by P 2501 »

Hello
I have a peugeot 306 xtdt (1997) which thus far has given very reliable service. However as i was driving home last night with the window open i could hear a sort of whistling noise as i accelerated from around 1500 rpm to 2000. It is a very high pitched noise and rises in tone with the engine note as i am accelerating.
I think it has got worse over the last couple of journeys because i could hear it on the way to work this morning with the windows closed!
My guess is one of the turbo pipes has cracked somewhere. I have had a look under the bonnet, but nothing seems amiss. I haven't revved the engine while i was looking - will do that tonight. Does anyone have any experience with this kind of thing? where to look etc.
the noise can be heard at idle and in neutral.
Thanks for any replies.
mgoodlad
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Post by mgoodlad »

Check your normal exhaust system - if a small hole has appeared somewhere there then you will hear the turbo whistle. The noise usually lags slightly behind the acceleration of the engine through the gears.
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Michael
yangreen
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Post by yangreen »

I back the exhaust theory. The Turbo isn't really doing a great deal below 2k revs.
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fastandfurryous
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Post by fastandfurryous »

Check your intercooler too. I have found a couple with splits in the plastic "side tanks" which have whistled like nobody's business. Not only does it make a horrible noise, but you'll be loosing boost pressure.
Revving the engine on no load will rarely get any kind of boost pressure up, so this is rather useless in this case. Also, as it's audible at idle, I back the "hole in the exhaust" theory too. The gasket between the turbo outlet elbow and the exhaust downpipe is a prime candidate for whistling. One of my old 405 td's whistled really loudly because of a worn gasket there.
mole42
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Post by mole42 »

I'd also take a look at the auxiliary belt pulleys. The bearings wear out and they shriek! My 405 diesel has squealed for the past two years - I've changed two of the pulleys but the bottom one is original and it makes a hell of a row.
You can check by puring water on the pulleys while the engine is running - the temporary lubrication will stop the noise if that's the cause of the trouble.
HTH
Richard
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Post by P 2501 »

Well, thanks to all who replied. It was the exhaust in the end. It had started blowing just before the cat very near to where it actually bolts on to the engine.
Once i had got underneath (ish) the car and revved the engine it was obvious what the trouble was. Whole exhaust pretty bad condition along its whole length, but in very poor nick by the cat.
I was fearing the worst when i took it in, and was quoted 179.99 for the cat alone, but the guys at brittania tyres in Derby managed to find me a straight piece of pipe with no cat and cobbled the whole thing together for 100 quid.
Seems to drive a fraction better now, but sounds "boomier" and a bit clatterier, but that doesn't bother me. Little bit more pull in higher gear too.
Thanks again.
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